Add.
There are many ways to solve this problem. Let's see two ways we can solve it. Place value table Let's line up the numbers by their decimal places. Ones $.$ Tenths ${3}$ $.$ ${5}$ $2$ $.$ ${4}$ Now, let's add each place value column. Ones $.$ Tenths ${{3}}$ $.$ ${5}$ $+$ ${2}$ $.$ ${4}$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $5$ $.$ $9$ Decomposing the numbers We can group the whole numbers together and the decimals together. $\begin{aligned} &({3} + {2}) + ({0.5} + {0.4})\\\\ &={5} + {0.9}\\\\ &=5.9 \end{aligned}$ $5.9 = 3.5 + 2.4$